In a variety of devices and systems, it can be useful to know an angular position of an element of the device or system. For example, in a directional antenna system, it can be important to determine an angular position of a directional antenna about an axis relative to another part of the system. Optical systems and weapons systems are other examples of systems in which it can be desirable to determine an angular position of an element. Some embodiments of the present invention are directed to improved apparatus and processes for determining an angular position of a gear to which such an element of a device or system can be attached.